Windows 7 Boot Manager can boot VHD's.
A VHD (virtual hard disk) is a normal file stored in the file system of the computer.
The VHD file when mounted is treated as a disk by the operating system (OS).
To create and mount (attach) a VHD you can use 'Disk Management'.
If a VHD is large enough you can install 32/64-bit Windows 7 (investigate for other OS's) on it.
A VHD is very handy if you want to experiment with 32/64-bit OS's, test software in different environments e.t.c.
A good reference about installing Windows 7 on VHD is:
How to install Windows 7 on a virtual hard disk (VHD) in 10 steps - Guides & Tutorials:
On my computer I have three OS's: XP, Windows 7 and Kubuntu plus a "Windows 7-VHD".
(Windows 7 VHD file is on XP partition.)
Here are some images from the Windows BCD (boot configuration data) store regarding the VHD.
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| 1. Windows 7 VHD Loader |
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| 2. Windows 7 VHD Recovery Loader |
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| 3. Windows 7 VHD Resume Loader |
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| 4. Windows 7 VHD Ramdisk options - object |
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| 5. Windows 7 VHD Ramdisk options - elements |
Some comments on the images:
- the utility used is "Visual BCD Editor" and can be downloaded here:
Visual BCD Editor - Windows 7 and Vista
- all relevant BCD objects (entries) were created by "Windows 7 install on VHD".
- the images are for reference - to know what 'good' Windows 7 VHD entries look like.
A Windows 7 install creates usually three loader entries in the BCD: an 'OS Loader', a 'Recovery Loader' and a 'Resume from Hibernation Loader'. The 'Ramdisk Options' object (entry) is needed for the 'Recovery Loader'.
image 1:
The Windows 7 VHD Loader is a normal Windows 7 Loader object with special values for the 'ApplicationDevice' and 'OSDevice' elements.
image 2, 4 and 5:
The Recovery loader entry specifies parameters for loading Windows Recovery Environment. The loaded file is WinRE.wim. Special mention for element 'RecoveryOs'=true - this element specifies that this entry(object) is a "recovery loader" - in the rest a recovery loader is a normal OS loader.
- 'ApplicationDevice' and 'OSDevice' refer to the ramdisk options through 'AddionalOptions' - compare {GUID} in image 2(form OSDevice) and image 4. (this could be a separate topic - Windows recovery loader - seems really complex).
image 3:
Resume from hibernation - loaded application is winresume.exe --> loads hiberfil.sys. (both files on VHD)
I helped discover this back when it was called custom:250000c2
ReplyDeleteProof: http://social.msdn.microsoft.com/Forums/en-US/windowsdeveloperpreviewgeneral/thread/e6e39a6c-013f-4beb-86bb-c15432643481
Peace,
Matt A. Tobin
Commanding Officer
Binary Outcast
I need more sleep. I thought this was the page for the Windows 8 bcd legacy bootmgr mode. I apologize. Please disregard and remove.
DeleteNo problem. I am not stating that I have discovered something - I am not Columbus or Newton.
ReplyDeleteYour discovery is yours.
My post is about this bloody element which is creating problems.
There are other elements and settings causing text-metro style to switch and Microsoft is not publishing anything on the subject. They know what they have created and keep the information secret(?).
People are having problems with Microsoft products - forums are full with threads about Windows problems !